Early embryonic development and cell differentiation Flashcards
What does the umbilical cord surrounded by
Layer of amnion
What does the umbilical car contain
- umbilical vein and arteries
- Allantois
- Vitello-intestinal duct
- Mesoderm from; amnion, yolk sac, and connecting stalk
Where does the extra-embryonic coelom persist in the umbilical cord
-what is it important in
Proximally
-Important in the development of the gut
What does the pericardial cavity house
The heart
What does the pleural cavity house
The lungs
What does the peritoneal cavity house
The gut tube
When do cells differentiate
During embryogenesis
What is ‘cleavage’
Process in which the zygote divides into multiple cells
What does cleavage trigger
embryonic differentiation
What process produces the three germ layers
Gastrulation
What are blastomeres
Cells which make up the blastocyst
What does the inner cell mass make
trilaminar disc
What does the trilaminar disc make
- mesoderm
- ectoderm
- endoderm
What does the endoderm form
- Epithelia of internal surfaces
e. g. respiratory system and urinary system
What does the ectoderm form
- Neuroectoderm
e. g. neural crest and the neural tube - Surface of the body
e. g. skin, hair, nails, mammary glands and pituitary
What does the mesoderm form
- Paraxial mesoderm (e.g. muscles of head, trunk, skeleton, dermis and connective tissue)
- Head mesoderm (e.g. skull, connective tissue and dentin)
- Intermediate mesoderm (e.g. urinogenital systen, ducts and accessory glands)
- Lateral mesoderm (e.g. connective tissue and muscle of viscera, serous membranes, heart, blood, spleen and adrenal cortex)
What is regulative development
-What does this do
Involves interaction of adjacent cells, within embryonic fields.
-Gives flexibility to differentiation
What are the two important characteristics of stem cells
- unspecialised and can divide repeatedly over long periods
- Under certain conditions, can be induced to differentiate into cells with special function
What are totipotent stem cells
Can differentiate into all cell types, plus extra embryonic cells e.g. zygote
What are pluripotent stem cells
Can give rise to all 3 germ layers but not embryonic (e.g. cells of the inner cell mass of the blastocyst where embryonic stem cells are derived)
What are multipoint stem cells
Can give rise to a restricted number of different cell types
What happens in therapeutic cloning or somatic nuclear transfer
- Nuclei from adult cells and introduce them into enucleated oocytes
- Oocytes are stimulated to differentiate into blastocysts, and ES cells are harvested
- BEcause cells are derived from host, they are not compatible genetically and because fertilization is not involved, the technique is less controversial
